Testing-box for underground electric cables



('No Model.)

W. J. MGELROY.

lTESTING BOX ECR UNDERGROUND ELECTRIC CABLES.

N0.284,l39. Patented Aug. 28, 1883.

u. PUERS. MLmquhw. www D. C.

UNITED STATES PATENT OFFICE.

VILLIAM J. MCELROY, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TOVTHE STANDARD CABLE COMPANY, OF NEV JERSEY.

TESTlNG-BOX FOR UNDERGROUND ELECTRIC CABLES.

SPECIFICATION forming part of Letters Patent No.'284,l39, dated August 28, 1883.

Application filed February 24, 1883.

To all whom it may concern:

Be it known that LWILLIAM J. McELRoY, a citizen of the United States, residing at Pittsburg, county ofAllegheny, `State rof Pennsyl- Vania, have invented or discovered a new and useful Improvementin Testing-Boxes for Un derground Electric Cables; and I do hereby declare the following to be a full, clear, concise, and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, in which-like letters indicating like parts-A Figure 1 is a view in elevation illustrative of my improved testing box or station. Fig. 2 is a top plan View, the cover of the box being removed; and Fig. 3 is a vertical sectional view.

My invention relates to certain improvements in testing-boxes for underground cables or electric conductors, and in general terms-it consists in certain combinations of a cast-iron box or case having downwardly-inclined tubular openings on its sides vfor ent ance of the cable, with a removable cap or cover, a supporting-block, an inclosed insulated board or stand, with provision for connecting the separate wires of the cable across the board and for preventing interference by induction between the exposed parts of the conductors, as hereinafter in ore fully describe d and claimed.

In the drawings, A', Fig. I, represents a section of earth in which is laid an electric cable, A. The cable shown is of the class known in the art as lead-covered, having insulated conducting-wires c inclosed within separate tubular passages in the body oi' lead covering. I do not wish, however, to limit the application of my inventionte cables oi' this class, as it may, if desired, be employed with underground cables of other kinds. The testingbox with which such cable is connected in my present invention is formed of a metal case, C, by preference of cylindrical form, having on its sides downwardly extending or inclined tubular openings c c, designed to admit the end of the cable into the interior of the case and afford an extended bearing-surface, with (No model.)

reference both to makinga secure attachment or connection, and also to preventing abrav sion or wearing away of the cable at the point of entering the box or case.

In order to make devices of this class easily accessible, it is customary to set them near the surface, where they may be subjected to considerable movement. If the cable be passed into the box through a simple hole in the side, it is diiiicult to secure the cable so that it will not break loose and open a leak; but by extending the tube or sleeve c from the side of the case, as shown, this diliiculty is eftectually overcome; also, byinelining these tubes downward provision is made for raising the cable near to the surface as it enters the box without unnecessary exposure of other points.

In order to make secure connection or attachment of the cable to the case, the tubular passage surrormding the cable may be filled with solder or lead, as at c.; or the tube and cable may be soldered together at the outer or inner end, or both, as at c?.

The ends of the cable within the case are subdivided longitudinally into separate leadcovered strands c', the ends of the inclosed conductors a being denudcd and `secured in bindingposts e, which are set or secured on a bed, E, of hard rubber or other good electric insulating material, electric connection being made across this bed or board by wires c', secured in opposite p osts. The insulating-bed E rests upon a metal plate, F, which latter is secured by screw f with a metal post, H, raised inthe center of the case or in its inclosed chamber.

In order to prevent' the evil. effects of induction due to the exposure of the wires across the bed or board E, metal plates are secured on its upper face by screws i', which extend through the bed and screw into tapped holes in the metal plate F, whereby the plates Q have electrical connection with ground. These plates fi are by preference about double the height of the wires c above the bed, and in length they extend in either direction to or a little beyond the ends of the lead armor of the strands c', thereby separating the wires will protect each wire from induction by reason of its proximity to other wires electrically excited. Any currents which may be induced in the plates i will be conducted to ground through the metallic connections provided, as above described.

The case or box is closed at the top by a removable eap or cover, D, secured by screwbolts d, or, if preferred, by screw-threaded flange d', run upon the corresponding thread, d2, on the' rim of the case by a spanner or other n Y c and removable cover D, a bed, E, of insusuitable tool applied to the raisedribs d3.

If desired, a gasket may be placed between I the cover and the 'rimof the ease to pack the joint and prevent leakage.

through them and into the timber.

which will be cheap, desirable, and easily replaced when required.

` Whenit is desired retest any one of 'thej wires of the cable, the earth above the box is thrown aside, the cover D removed, the Wire? These plates by their presence will In order to support the case or box firmly and prevent movement, it is seated on the end of a post, B, and; secured thereto by tangs'z, nails being driven In itti'ng' the ease or box on the post the latter is by preference dressed down to the size and shape of the former, lor to a little less size, so itliatl -andalso Awithin the box, moisture will be effectually excluded, induction between. conductors prevented, andthe several conductors be easily accessible for such purposes as may arise in the use of the cable. i

I claim herein as my inventionl. `In a cable-testing box, the combination of metal case C, having tubular cable-passages lating material, secured within the case, binding-post c, secured to s uch bed, and inductionplates i between lines of posts, substantially 'as Set forth.

2. The 'combination of metal case C, havingpk openings therein for insertion of the cable te1`1d:=1,with inclosed metal support H, metal plate F, secured. to the support, bed E, of in- 6o sulating material, resting on the plate, bind- Vi'r'l'g-pos'tse, and 'induction-plates i, substantially as'and 1for the purposes set forth.

3. The :case C, having tubular openings c and tangs ca extending downward therefrom,

in combinationwith post B vand cables A, substantially as set forth.

In testimony' whereof I Ahave hereunto set my hand.

WILLIAM J. MCELROY. 

